1. Field of the Invention
The invention relates generally to a method of manufacturing semiconductor devices and, more particularly, to a method of forming a trench type isolation film of a semiconductor device that can improve the leakage characteristic of the isolation film.
2. Discussion of Related Art
If a typical etch process for forming a trench type isolation film is performed, ions can be concentrated on the sidewalls of the trench since electrons are charged on the sidewalls of the trench, or a micro trench may be formed on the sidewalls since the sidewalls are rapidly cooled due to ion scattering.
In a typical etch process for forming a trench type isolation film, an etch barrier layer is formed below a subject film to be etched so that an over-etch process can be carried out. Accordingly, although the micro trench is formed during the etch process, the micro trench can be removed by the over-etch process. It is therefore possible to form a flat bottom profile of the trench.
However, the trench etch process for element isolation employs a partial etch process for etching only a predetermined amount of the subject film. Accordingly, it is impossible to remove the micro trench.
While a series of processes, such as a sidewall oxidation process, a trench burial process employing a high density plasma (HDP) oxide film and an annealing process, which will be performed subsequently, stress is concentrated on the micro trench. The portion of the micro trench causes dislocation, resulting in degraded leakage characteristics of the isolation film.